Introduction: Tower of Hanoi
Grand Prize in the
I was first introduced to this puzzle by my wife's grandmother. The way I recall it is that we were sitting, talking for a while and she just sort of randomly got up, went to the shelf, and brought back this strange looking wooden thing. "Figure it out," she said. "All the pieces have to make it to the other side, one at a time, and a smaller one can never go below a bigger one." I spent the next couple hours trying and failing.
Now, about five years later, I have finally gotten around to making my own version of this classic puzzle. It's incredibly simple in its construction but it can be incredibly challenging in its execution. Truly, a fascinating brain teaser.
Altogether, the build took me about an hour including documenting time, so it's a pretty quick and simple project.
Step 1: Materials and Tools
Here's a list of the materials and tools I used for this project.
- Wooden Board: I used pine because it's cheap and I had it on hand already. If you make yours the same way I made mine, you'll need around three feet of board.
- Dowel Rod: Available from just about anywhere for a little more than pocket change.
- A Drill
- Drill Bits: You need one drill bit that is the same diameter as the dowel rod you bought, mine was 5/16", and another one that is slightly bigger, mine was 3/8".
- A Saw: I actually used a table saw to make most of my cuts, but you could use any kind of wood saw, just know that your cuts may not be square
- A Square and/or Ruler: My square doubles as my ruler most of the time
- Wood Glue
- Wood Finish: I used polyurethane because it's easy to use and I had some on hand, but you can use tung oil, paint, various stains, and a whole host of others
Please be careful while working with sharp tools. Obviously, a saw can cut skin and a drill can pierce skin so please use caution and your brain while you are working with the tools.
Please note that you will often see the tower made with circles instead of squares. Other than aesthetic value, this has no bearing on the puzzle and squares are easier to make than circles so that's what I did.
Step 2: Cutting
Take your board and cut it to length. I cut mine to 12" long by about 5" wide.
Take the leftover two feet of board and cut the squares that will make up the towers. I cut mine in decreasing sizes of a half inch each time. So my largest square is 4" the next one is 3 1/2" and so forth all the way down to 1 1/2". I made six squares altogether because I've only ever figured out how to solve the puzzle with five. Once I figure it out with six, I'll probably make another piece to continue on in the challenge. You can make the puzzle with as many pieces as you like, but they are commonly made with 7-9.
Last but not least, cut your dowel rod to length. I cut mine into three sections at 7" each.
Step 3: Drilling
Mark the center of your squares by placing a straight edge corner to corner on each one and striking a line. then cross the straight edge over and do the same thing on the opposite corners. This will make a nice clean X in the wood with the center being where the X crosses.
Take the largest wood square and place it on one end of the one foot long board, marking where it comes to. Measure and mark the halfway point between where the wood square's edge comes to and the edge of the one foot board, then repeat the process on the other side. If you cut accurately, which I did not, it should be about 2 1/2". Measure half of the width of the board and mark that as well forming a small X where the two measurements meet. Last but not least, measure and mark the halfway point of both the length and the width of the entire board, about 6" by 5" and make one more small X where those measurements meet.
After all that, you can finally drill your holes. Drill all the way through the one foot board with the 5/16" drill bit in the center of the little X's you made and with the 3/8" drill bit in the center of the big X's on the squares.
Step 4: Optional Step: Sprucing Up
I decided to go ahead and run all the pieces over my belt sander to clean them up a bit. I also decided to run them through the router to make them a little more eye catching. The game obviously plays just fine without these additions, but I like the way things turned out.
Step 5: Gluing
Probably the easiest step involved. put some glue on the ends of your dowel rods, push them into the holes on the one foot board and wait for them to dry.
Step 6: Optional Step: Finishing the Wood
There are several different ways you could choose to finish the wood. You can leave it all natural and not put anything on it, you can stain it with a wood stain to make it a different color, you could paint it, clear coat it, or rub some kind of oil into it. For mine, I decided to spray it with clear polyurethane. I gave it two generous coats on one side, let all the pieces dry, flipped them all over, and repeated. Then gave everything a light going over with steel wool to get rid of any burrs that were left in the wood.
Step 7: Playing the Game
All that's left to do is give it a try! The rules are pretty simple: The object is to get all the pieces from one side to the other. You can only move one piece at a time and it must be the uppermost piece on the stack. A smaller piece can never be below a larger one. All pieces have to be on the pegs unless they are being moved. I've included example pictures that detail how to solve it with three pieces in seven moves, but beyond that, you're on your own.
Step 8: Final Notes
This is an incredibly fun little puzzle. It's easy to make and play, but challenging to solve. One of the great things about it is that you can't figure out how to solve it by building it, so the project makes a puzzle that is just as fun for you as it is for anybody else. I hope you enjoyed the build, and enjoy the puzzle!
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